<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>盒子宽与高</title>
<style type="text/css">
.box{
	width:200px;
	height:80px;
	background:#ccc;
	border:8px solid #f00;
	padding:15px;
	margin:20px;}

</style>
</head>

<body>
<p class="box">这是一个盒子。</p>
</body>
</html>
